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    <script>

        // isPrototypeOf()     判断是不是某个对象的原型对象

        const arr = [1,2,3] ;

        const res = Array.prototype.isPrototypeOf(arr) ;

        console.log(res);



        // 判断数组?????????
        
        //    Array.isArray()  

        //    Array.prototype.isPrototypeOf(a) 

        //    construtor

        //    instanceof



        console.log(arr instanceof Array);


        console.log(arr.constructor === Array);

    </script>
    
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